Check that adjacency matrices given by the user are valid.

[ismael-lajaaiti]

Add a safety check inside MultiplexNetwork to ensure that the adjacency matrix provided by the user for non-trophic interactions are valid.

[ismael-lajaaiti]

To complete, the idea is the non-trophic interactions are constrained by certain rules, which are:

• competition can only occur between sessile species (currently producers <=> sessile)
• facilitation can only be directed toward a producer
• interference can only occur between two predators that share a common prey
• refuge can only be directed toward a prey and coming from a sessile species (i.e. a producer)

[iago-lito]

• trophic: no cycles?

[iago-lito]

Could be featured as #77 gets addressed.

[iago-lito]

The consistency enforced by #131 api should solve this.